iPad mini as RAW backup

Based on my recent 10 day visit to Switzerland I would have thought the overall capacity of the iPad would be much too small for a 5 month trip, I am using a D800E so nef files are large but I came home with over 120 Gb of image files and my wife with a D800 had just over 100 Gb to her name. We take a rMBP and off load the images to the internal SSD and a backup copy is made to an external bus driven HD.